The dog is a 7mo old Australian Shepherd. I am her third owner. She was not mistreated but obviously mishandled. I have done pretty well traing other dogs but am having trouble with this one. When I first met her she was aggressive and did not like strangers. It took me about 10min to get her to submit and be calm for me, but now all she does is submit when I ask her to do anything. How can we overcome this behavior?